Mtsooning RV Brass Vacuum Breaker Check Valve 571-VAC-CHK-A — Inline Backflow Preventer, 8–125 PSI

The Mtsooning 571-VAC-CHK-A is a brass RV vacuum breaker check valve designed to stop backflow into your freshwater line and protect black-tank flushing systems.

When flushing an RV black tank or connecting a freshwater inlet to a tank flusher, unwanted backflow or siphoning can contaminate potable water and damage plumbing. The Mtsooning 571-VAC-CHK-A provides a simple, durable barrier: it permits flow in the intended direction while preventing waste or wastewater from reversing into the freshwater feed. Built from brass and rated for typical RV water pressures, this check valve is a direct, compact solution for camper, travel trailer, and motorhome plumbing reliability.

How does this valve prevent backflow during black tank flushing?

The check valve opens when freshwater is pushed toward the tank flusher and closes automatically if pressure drops or suction tries to pull liquid back. That one-way action blocks any waste or contaminated fluid from traveling upstream into your freshwater plumbing. It acts as a passive safeguard without moving parts that need power.

• One-way check design prevents reverse flow into freshwater inlet
• Automatically seals when pressure drops or siphoning occurs
• Installs inline between the freshwater inlet and tank flusher

Is the Mtsooning 571-VAC-CHK-A durable enough for RV water systems?

Yes — the valve is machined from brass to resist corrosion and handle the pressures common in RV systems. Its construction tolerates typical freshwater pressures from 8 to 125 PSI, which covers city hookups, onboard pumps, and most service conditions. That material choice reduces the risk of leaks and extends service life compared with plastic alternatives.

• Brass body for corrosion resistance and long-term durability
• Rated to withstand 8–125 PSI operating pressures
• Suitable for intermittent outdoor exposure in RV plumbing bays

Where and how should I install the vacuum breaker check valve?

Mount the valve inline at the freshwater inlet, positioned at least six inches above the highest connected point to the waste tank to maintain proper vacuum-breaking action. Orient the valve so its flow direction arrow points toward the tank flusher. Use compatible fittings and thread sealant appropriate for potable water plumbing to ensure a leak-free connection.

• Install at least 6 inches above the highest point connected to the waste tank
• Align flow arrow toward the tank flusher; use proper potable-water fittings
• Replace a leaking or old breaker check valve to restore backflow protection

Which RVs and situations is this valve compatible with?

The 571-VAC-CHK-A is intended as a replacement or upgrade for many RV models, campers, travel trailers, and motorhomes that use a black tank flushing arrangement or freshwater inlet. It’s a compact retrofit part that fits where inline backflow prevention is required. Check thread sizes and connection types to confirm fitment before purchase or bring the old valve to match exact fittings.

• Designed for RVs, campers, travel trailers, and motorhomes
• Works as a replacement for existing black tank flush breaker valves
• Confirm thread size and fitting compatibility during installation

Who is this for? The Mtsooning 571-VAC-CHK-A is aimed at RV owners, DIY plumbers, and service technicians who want a dependable, low-maintenance way to protect freshwater lines during black-tank flushing. If you need an inline, brass backflow preventer that tolerates typical RV water pressures and installs quickly where freshwater meets tank-flush assemblies, this valve offers a compact, long-lasting option. It’s especially useful when an existing vacuum breaker leaks or when you’re upgrading to more durable materials for seasonal RV maintenance.